code: def test_determinism_source_date_epoch(fmt, string):
      """
      Test SOURCE_DATE_EPOCH support. Output a document with the environment
      variable SOURCE_DATE_EPOCH set to 2000-01-01 00:00 UTC and check that the
      document contains the timestamp that corresponds to this date (given as an
      argument).
  
      Parameters
      ----------
      fmt : {"pdf", "ps", "svg"}
          Output format.
      string : bytes
          Timestamp string for 2000-01-01 00:00 UTC.
      """
      buf = subprocess.check_output(
          [
              sys.executable,
              "-R",
              "-c",
              f"from matplotlib.tests.test_determinism import _save_figure; "
              f"_save_figure('', {fmt!r})",
          ],
          env={
              **os.environ,
              "SOURCE_DATE_EPOCH": "946684800",
              "MPLBACKEND": "Agg",
          },
      )
      assert string in buf
  
file_path: matplotlib/lib/matplotlib/tests/test_determinism.py
imports: import os
  import subprocess
  import sys
  import pytest
  import matplotlib
  import matplotlib.testing.compare
  from matplotlib import pyplot
  from matplotlib.testing._markers import needs_ghostscript, needs_usetex
label_desc: Use image node_id 3 for calling a global function with example usage: test_determinism_source_date_epoch(fmt, string) without return types